This invention relates to a pressurization apparatus for a positive expulsion tank for a monopropellant fuel powered system.
Positive expulsion tanks have been used in systems for supplying propellant components to rocket engines. Stored gas or evaporable liquids have been used to provide the pressurization gas for the positive expulsion tank. These systems require bulky storage containers or complicated high cost pressurization apparatus.
Positive expulsion tanks have been used in auxiliary power units, such as starters for aircraft. In these devices, positive expulsion tanks have been used to supply a monopropellant to a catalyst pack wherein the monopropellant is decomposed to supply a driving gas for the starter turbine. After the operation of the auxiliary power unit is completed, the catalyst pack is flushed with nitrogen gas to purge any monopropellant products which might poison the catalyst pack. This provides a longer life for the catalyst pack.